util.h File Reference

#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <das3/defs.h>

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Data Structures
struct	das_error_msg
	Structure returned from das_get_error(). More...

Macros
#define	DASERR_DIS_EXIT   0
	Used to indicate that errors should trigger program exit.
#define	DASERR_DIS_RET   1
	Used to indicate that errors should trigger library functions to return error values.
#define	DASERR_DIS_ABORT   43
	Used to indicate that errors should trigger program abort with a core dump.
#define	das_error(nErrCode, ...)    das_error_func(__FILE__, __func__, __LINE__, nErrCode, __VA_ARGS__ )
	Signal an error condition.
#define	das_error_str(nErrCode, sMsg)    das_error_func_fixed(__FILE__, __func__, __LINE__, nErrCode, sMsg)
	Signal an error condition with a message that is not a format string.
#define	das_error_false(nErrCode, ...)    (das_error_func(__FILE__, __func__, __LINE__, nErrCode, __VA_ARGS__), false)
	Raise an error and return false, for a function that reports failure as a bool rather than a DasErrCode.
#define	das_error_null(nErrCode, ...)    (das_error_func(__FILE__, __func__, __LINE__, nErrCode, __VA_ARGS__), NULL)
	Raise an error and return NULL, for a function that answers with a pointer.
#define	das_within(A, B, E)   (fabs((A) - (B)) < (E) ? true : false)
	Check to see if two floating point values are within an epsilon of each other.
#define	DAS_XML_BUF_LEN   1000000
	The limit on xml packet length, in bytes.
#define	DAS_XML_NODE_NAME_LEN   256
	The limit of xml element name length, in bytes.
#define	DAS_MAX_ID_BUFSZ   64
	The size of an char buffer large enough to hold valid object IDs.

Typedefs
typedef void(*	das_log_handler_t) (int nLevel, const char *sMsg, bool bPrnTime)
	Definition of a message handler function pointer.

Functions
DAS_API void	das_init (const char *sProgName, int nErrDis, int nErrBufSz, int nLevel, das_log_handler_t logfunc)
	Initialize any global structures in the Das2 library.
DAS_API const char *	das_version (void)
	Return the version of this library.
DAS_API void	das_finish (void)
	A do nothing function on Unix, closes network sockets on windows.
DAS_API void	das_abort_on_error (void)
	Error handling: Trigger Core Dumps.
DAS_API void	das_exit_on_error (void)
	Error handling: Normal Exit Set the library to call exit(ErrorCode) when a problem is detected.
DAS_API void	das_return_on_error (void)
	Error handling: Normal Return Set the library to return normally to the calling function with a return value that indicates a problem has occurred.
DAS_API int	das_error_disposition (void)
	Error handling: get the library's error disposition.
DAS_API void	das_errdisp_get_lock (void)
	Used for co-operative locking of time-limited error disposition changes.
DAS_API void	das_errdisp_release_lock (void)
	Used for co-operative locking of time-limited error disposition changes.
DAS_API void	das_error_setdisp (int nDisp)
	The inverse of das_error_disposition.
DAS_API void	das_print_error (void)
	Error handling: Print formatted error to standard error stream Set the library to output formatted error messages to the processes standard error stream.
DAS_API bool	das_save_error (int maxmsg)
	Error handling: Save formatted error in a message buffer.
DAS_API const char *	das_lib_version (void)
	Get the library version.
DAS_API bool	das_assert_valid_id (const char *sId)
	Check that a string is suitable for use as an object ID.
DAS_API void	das_store_str (char **psDest, size_t *puLen, const char *sSrc)
	Store string in a buffer that is reallocated if need be.
DAS_API char *	das_string (const char *fmt,...)
	Allocate a new string on the heap and format it.
DAS_API char *	das_strip (char *sLine, char cComment)
	Strip whitespace from a string.
DAS_API size_t	das_tokncpy (char *dest, const char *src, size_t n)
	Copy string as an XML token.
DAS_API const char *	das_xml_escape (char *dest, const char *src, size_t uOutLen)
	Translate unsafe characters for XML string output.
DAS_API char *	das_strdup (const char *sIn)
	Copy a string into a new buffer allocated on the heap.
DAS_API uint8_t *	das_memset (uint8_t *pDest, const uint8_t *pSrc, size_t uElemSz, size_t uCount)
	A memset that handles multi-byte items
DAS_API char *	das_vstring (const char *fmt, va_list ap)
	Store a formatted string in a newly allocated buffer.
DAS_API bool	das_isdir (const char *path)
	Is the path a directory.
DAS_API DasErrCode	das_mkdirsto (const char *path)
	Insure directories to a specific location exist.
DAS_API const char *	das_userhome (void)
	Get the home directory for the current account.
DAS_API bool	das_copyfile (const char *src, const char *dest, mode_t mode)
	Copy a file to a destination creating directories as needed.
DAS_API bool	das_isfile (const char *path)
	Is the path a file.
DAS_API int	das_dirlist (const char *sPath, char ppDirList[][256], size_t uMaxDirs, char cType)
	Get a sorted directory listing.
DAS_API double	das_strtod_c (const char *nptr, char **endptr)
	A C locale string to double converter.
DAS_API char *	das_b64_encode (const unsigned char *data, size_t input_length, size_t *output_length)
	Encode binary data as base64 (RFC 4648) characters in a new buffer.
DAS_API int	das_b64_decode_buf (const char *data, size_t input_length, unsigned char *out, size_t out_cap, size_t *output_length)
	Decode base64 (RFC 4648) into a caller-provided buffer, no allocation.
DAS_API unsigned char *	das_b64_decode (const char *data, size_t input_length, size_t *output_length)
	Decode base64 (RFC 4648) into a newly allocated buffer, symmetric with das_b64_encode.
bool	dascmd_isArg (const char *sArg, const char *sShort, const char *sLong, bool *pLong)
	See a given string matches the short or long form of an option.
bool	dascmd_getArgVal (char *sDest, size_t uDest, char **argv, int argc, int *pArgIdx, const char *sShort, const char *sLong)
	Get the value of an argument if the current entry in argv matches either the short or long form of an option.

Macro Definition Documentation

das_error

#define das_error	(		nErrCode,
			...
	)		das_error_func(__FILE__, __func__, __LINE__, nErrCode, __VA_ARGS__ )

Signal an error condition.

This routine is called throughout the code when an error condition arrises.

The default handler for error conditions prints the message provided to the standard error channel and then calls exit(nErrCode). To have the library call your handler instead use the das_set_error_handler() function. To have the library abort with a core dump on an error use das_abort_on_error().

Each source file in the code has it's own error code. Though it's probably not that useful to end users, the codes are provided here:

• 8 : Not yet implemented - DASERR_NOTIMP
• 9 : Assertion failures - DASERR_ASSERT
• 11 : Lib initialization - DASERR_INIT
• 12 : buffer.c - DASERR_BUF
• 13 : util.c - DASERR_UTIL
• 14 : encoding.c - DASERR_ENC
• 15 : units.c - DASERR_UNITS
• 16 : descriptor.c - DASERR_DESC
• 17 : plane.c - DASERR_PLANE
• 18 : packet.c - DASERR_PKT
• 19 : stream.c - DASERR_STREAM
• 20 : oob.c - DASERR_OOB
• 22 : io.c - DASERR_IO
• 23 : dsdf.c - DASERR_DSDF
• 24 : dft.c - DASERR_DFT
• 25 : log.c - DASERR_LOG
• 26 : array.c - DASERR_ARRAY
• 27 : variable.c - DASERR_VAR
• 28 : dimension.c - DASERR_DIM
• 29 : dataset.c - DASERR_DS
• 30 : builder.c - DASERR_BLDR
• 31 : http.c - DASERR_HTTP
• 32 : datum.c - DASERR_DATUM
• 33 : value.c - DASERR_VALUE
• 34 : operator.c - DASERR_OP
• 35 : credentials.c - DASERR_CRED
• 36 : node.c - DASERR_NODE
• 37 : time.c - DASERR_TIME
• 38 : property.c - DASERR_PROP
• 39 : context.c - DASERR_CTX
• 40 : vector.c - DASERR_VEC
• 41 : serial.c - DASERR_SERIAL
• 42 : iterator.c - DASERR_ITER
• 43 : spice.c - DASERR_SPICE
• 44 : uri.c - DASERR_URI
• 45 : form*.c - DASERR_FORM
• 46 : generator.c - DASERR_GEN

Application programs are recommended to use values 64 and above to avoid colliding with future das2 error codes.

Parameters

nErrCode

The value to return to the shell, should be one of the above.

Returns

By default this function never returns but if the Das2C error disposition has been set to DAS2_ERRDIS_RET then the value of nErrCode is returned.

das_error_str

#define das_error_str	(		nErrCode,
			sMsg
	)		das_error_func_fixed(__FILE__, __func__, __LINE__, nErrCode, sMsg)

Signal an error condition with a message that is not a format string.

Use this when the message comes from elsewhere (a caller, a parser, a library) and may contain '' characters. Nothing is interpreted.

See also

das_error

das_error_false

#define das_error_false	(		nErrCode,
			...
	)		(das_error_func(__FILE__, __func__, __LINE__, nErrCode, __VA_ARGS__), false)

Raise an error and return false, for a function that reports failure as a bool rather than a DasErrCode.

return das_error(...) is correct in the DasErrCode functions that are most of this library, and silently WRONG in a bool one: das_error() hands back a non-zero code, which as a bool is true, so the failure reports success. The types are both integers and no compiler diagnostic exists for it. Write return das_error_false(...) in a bool function and the question does not come up.

das_error_null

#define das_error_null	(		nErrCode,
			...
	)		(das_error_func(__FILE__, __func__, __LINE__, nErrCode, __VA_ARGS__), NULL)

Raise an error and return NULL, for a function that answers with a pointer.

See also

das_error_false

DAS_XML_BUF_LEN

#define DAS_XML_BUF_LEN   1000000

The limit on xml packet length, in bytes.

(ascii encoding.)

Typedef Documentation

das_log_handler_t

typedef void(* das_log_handler_t) (int nLevel, const char *sMsg, bool bPrnTime)

Definition of a message handler function pointer.

Message handlers need to be prepared for any of the string pointers sMsg, sDataStatus, or sStackTrace to be null.

Parameters

nLevel	The message level. If nLevel is equal to or greater than das_log_getlevel() then the message should be logged.
sMsg	The message, usually not null.
bPrnTime	The current system time should be included in the log output.

Function Documentation

das_init()

DAS_API void das_init	(	const char *	sProgName,
		int	nErrDis,
		int	nErrBufSz,
		int	nLevel,
		das_log_handler_t	logfunc
	)

Initialize any global structures in the Das2 library.

This should be the first function your program calls before using any Das2C functions. In general Das2C tries to avoid global structures but does use them in following areas:

• Error and log handling - Since the error and logging disposition should be the same for all library calls handlers are set here
• Unit conversions - Since das_unit variables should be comparable using a simple equality test, a global registry of const char pointers is needed
• TT2000 leapsecond table - To avoid rebuilding the library after each leapsecond is announced, an external table defined by the environment variable CDF_LEAPSECONDTABLE is loaded, if the variable is defined.
• FFTW plan mutexes - Since the FFTW library unfortunately uses global plan memory
• OpenSSL Context mutexes - The openssl library context cannot be changed by multiple threads at the same time, a mutex is setup to prevent this from happening

This function initializes defaults for the items above.

Parameters

sProgName	The name of the program using the library. Used in some error messages.
nErrDis	Set the behavior the library takes when an error is encountered. May be one of DASERR_DIS_EXIT, call exit() when an error occurs; DASERR_DIS_RET, return with an error code; or DASERR_DIS_ABORT, call abort(). The value of DASERR_DIS_EXIT is 0 so you can use that for the default behavior. If DASERR_DIS_RET is used, the function das_get_error() can be used to retrieve the most recent error message.
nErrBufSz	If not zero, a global error message buffer will be allocated that is this many bytes long and error message will be saved into the buffer instead of being sent to the standard error channel. Messages can be retrieved via das_get_error(). If zero, these will be send to the standard error channel as soon as they occur. Saving errors is only useful if the error disposition is DAS2_ERRDIS_RET as otherwise the program exits before the message can be output.
nLevel	Set the logging level to one of, DASLOG_TRACE, DASLOG_DEBUG, DASLOG_NOTICE, DASLOG_WARN, DASLOG_ERROR, DASLOG_CRITICAL.
logfunc	A callback for handling log messages. The callback need not be thread safe as it will only be triggered inside mutual exclusion (mutex) locks. If NULL messages are printed to the standard error channel.

The error disposition does not affect any errors that are encountered within das_init. Errors should not occur during initialization, any that do trigger a call to exit()

das_abort_on_error()

DAS_API void das_abort_on_error

(

void

)

Error handling: Trigger Core Dumps.

Call this function to have the library exit via an abort() call instead of using exit(ErrorCode). On most systems this will trigger the generation of a core file that can be used for debugging.

Warning

: Calling this function prevents open file handles from being flushed to disk which will typically result in corrupted output.

das_exit_on_error()

DAS_API void das_exit_on_error

(

void

)

Error handling: Normal Exit Set the library to call exit(ErrorCode) when a problem is detected.

This is usually what you want and the library's default setting.

das_return_on_error()

DAS_API void das_return_on_error

(

void

)

Error handling: Normal Return Set the library to return normally to the calling function with a return value that indicates a problem has occurred.

This will be the new default, but is not yet tested.

das_error_disposition()

DAS_API int das_error_disposition

(

void

)

Error handling: get the library's error disposition.

Returns

one of the following integers:

• DAS2_ERRDIS_EXIT - Library exits when there is a problem
• DAS2_ERRDIS_ABORT - Library aborts, possibly with core dump on a problem
• DAS2_ERRDIS_RET - Library returns normally with an error code

das_errdisp_get_lock()

DAS_API void das_errdisp_get_lock

(

void

)

Used for co-operative locking of time-limited error disposition changes.

Acquire this lock before your critical section, then release it. All code that want's to toggle the error disposition should use this, but it's not enforceable, except by code review.

YOU MUST BE SURE YOUR FUNCTION CAN'T EXIT BEFORE THE LOCK IS RELEASED!

das_errdisp_release_lock()

DAS_API void das_errdisp_release_lock

(

void

)

Used for co-operative locking of time-limited error disposition changes.

Release this lock before your critical section, then release it. All code that want's to toggle the error disposition should use this, but it's not enforceable, except by code review.

das_error_setdisp()

DAS_API void das_error_setdisp

(

int

nDisp

)

The inverse of das_error_disposition.

Parameters

nDisp

One of DAS2_ERRDIS_EXIT, DAS2_ERRDIS_ABORT, DAS2_ERRDIS_RET

das_print_error()

DAS_API void das_print_error

(

void

)

Error handling: Print formatted error to standard error stream Set the library to output formatted error messages to the processes standard error stream.

This is the default.

das_save_error()

DAS_API bool das_save_error

(

int

maxmsg

)

Error handling: Save formatted error in a message buffer.

Set the library to save formatted error message to a message buffer.

Parameters

maxmsg

maximum message size. The buffer created will be maxmsg in length, meaning any formatted messages longer than the available buffer size will be truncated to maxmsg-1

Returns

true if error buffer setup was successful, false otherwise.

das_lib_version()

DAS_API const char * das_lib_version

(

void

)

Get the library version.

Returns

the version tag string for the das2 core library, or the string "untagged" if the version is unknown

das_assert_valid_id()

DAS_API bool das_assert_valid_id

(

const char *

sId

)

Check that a string is suitable for use as an object ID.

Object ID strings are ascii strings using only characters from the set a-z, A-Z, 0-9, and _. They do not start with a number. They are no more than 63 bytes long. Basically they can be used as variable names in most programming languages.

If the das_error_disposition is set to exit this function never returns.

Parameters

sId

Returns

True if the string can be used as an ID, false otherwise.

das_store_str()

DAS_API void das_store_str	(	char **	psDest,
		size_t *	puLen,
		const char *	sSrc
	)

Store string in a buffer that is reallocated if need be.

Parameters

psDest	a pointer to the storage location
puLen	a pointer to the size of the storage location
sSrc	the source string to store.

das_string()

DAS_API char * das_string	(	const char *	fmt,
			...
	)

Allocate a new string on the heap and format it.

Except for using das_error on a failure, this is a copy of the code out of man 3 printf on Linux.

Returns

A pointer to the newly allocated and formatted string on the heap, or NULL if the function failed and the das2 error disposition allows for continuation after a failure

das_strip()

DAS_API char * das_strip	(	char *	sLine,
		char	cComment
	)

Strip whitespace from a string.

Parameters

sLine	- Pointer to a writable null terminated string, or a NULL pointer.
cComment	- Treat the character if it was a null character terminating the string. Replace it with an actual null if found. Use '\0' to avoid stripping "comments".

Returns

NULL if the string consisted only of whitespace, or was empty or was a NULL pointer. Otherwise a pointer to the first non-whitespace portion is returned. A null character will be written to the string at the start of trailing whitespace.

das_tokncpy()

DAS_API size_t das_tokncpy	(	char *	dest,
		const char *	src,
		size_t	n
	)

Copy string as an XML token.

Copy a string ignoring leading and traily spaces. Internal whitespace characters are converted to regular spaces and collapsed

Parameters

dest	The buffer to receive string data, may be UTF-8 if desired The output string is always null terminated if n > 1
src	the source string, may be UTF-8 if desired
n	the size of the dest buffer

Returns

the equivalent of strlen(dest).

das_xml_escape()

DAS_API const char * das_xml_escape	(	char *	dest,
		const char *	src,
		size_t	uOutLen
	)

Translate unsafe characters for XML string output.

At present only the characters set [ " < > & ] are translated. All white space characters are preserved. So long as dest is at least one byte long the result is null terminated.

Parameters

dest	The buffer to receive the output
src	The data source
uOutLen	the size of the dest buffer.

Returns

the parameter dest cast to a constant pointer.

das_strdup()

DAS_API char * das_strdup

(

const char *

sIn

)

Copy a string into a new buffer allocated on the heap.

Parameters

sIn	the string to copy

Returns

a pointer to the newly allocated buffer containing the same characters as the input string or NULL if the input length was zero

das_memset()

DAS_API uint8_t * das_memset	(	uint8_t *	pDest,
		const uint8_t *	pSrc,
		size_t	uElemSz,
		size_t	uCount
	)

A memset that handles multi-byte items

Uses memcpy because the amount of data written in each call goes up exponentially and memcpy is freaking fast, much faster than a linear write loop for large arrays.

Parameters

pDest	The destination area must not overlap with pSrc
pSrc	A location for an individual element to repeat in pDest
uElemSz	The size in bytes of a single element
uCount	The number of elements to repeat in pDest

Returns

The input pDest pointer. There is no provision for a NULL return as this function should not fail since the memory is pre-allocated by the caller

das_vstring()

DAS_API char * das_vstring	(	const char *	fmt,
		va_list	ap
	)

Store a formatted string in a newly allocated buffer.

This version is suitable for calling from variable argument functions.

Except for using das_error on a failure, this is a copy of the code out of man 3 printf on Linux.

Parameters

fmt	- a printf format string
ap	A va_list list, see vfprintf or stdarg.h for details

Returns

A pointer to the newly allocated and formatted string on the heap, or NULL if the function failed and the das2 error disposition allows for continuation after a failure

das_isdir()

DAS_API bool das_isdir

(

const char *

path

)

Is the path a directory.

Parameters

path	The directory in question, passed to stat(2)

Returns

true if path can be determined to be a directory, false otherwise

das_mkdirsto()

DAS_API DasErrCode das_mkdirsto

(

const char *

path

)

Insure directories to a specific location exist.

Parameters

sPath

a full path to a file. If this string contains no path separators, the function does nothing.

Returns

true if directories up to the final location either exist, or could be generated, false otherwise.

das_userhome()

DAS_API const char * das_userhome

(

void

)

Get the home directory for the current account.

Returns

A pointer to a global string that is the current user's home directory, or other likely writable location if the home directory could not be determined.

das_copyfile()

DAS_API bool das_copyfile	(	const char *	src,
		const char *	dest,
		mode_t	mode
	)

Copy a file to a destination creating directories as needed.

If the files exists at the destination it in overwritten. Directories are created as needed. Directory permissions are are the same as the file with the addition that for each READ permission in the mode, directory EXEC permission is added.

Parameters

src	- name of file to copy
dest	- name of destination
mode	- the permission mode of the destination file, 0664 is recommended if you can decide on the output permissions mode. (mode argument not present in WIN32 version)

Returns

- true if the copy was successful, false otherwise.

das_isfile()

DAS_API bool das_isfile

(

const char *

path

)

Is the path a file.

Parameters

path	The file in question, passed to stat(2)

Returns

true if path can be determined to be a file, false otherwise

das_dirlist()

DAS_API int das_dirlist	(	const char *	sPath,
		char	ppDirList[][256],
		size_t	uMaxDirs,
		char	cType
	)

Get a sorted directory listing.

Parameters

sPath	The path to the directory to read.
ppDirList	A pointer to a 2-D character array where the first index is the directory item and the second index is the character position. The max value of the second index must be = NAME_MAX - 1. The value NAME_MAX is defined in the POSIX header limits.h
uMaxDirs	The maximum number of directory entries that may be stored
cType	May be used to filter the items returned. If cType = 'f' only files will be return, if cType = 'd' then only directories will be returned. Any other value, including 0 will return both.

Returns

On success the number of items in the directory not counting '.' and '..' are returned, on failure a negative error code is returned. Item names are sorted before return.

das_strtod_c()

DAS_API double das_strtod_c	(	const char *	nptr,
		char **	endptr
	)

A C locale string to double converter.

This is essentially the same as the C-lib function strtod, except it always evaluates strings in the "C" locale no matter the current locale of the program. It does not alter the current program's locale.

Parameters

nptr	The starting point of the string to convert
endptr	Where to store a pointer to the last item converted

Returns

The converted value

Notes: Errno is set as normal for the underlying strtod implementation.

das_b64_encode()

DAS_API char * das_b64_encode	(	const unsigned char *	data,
		size_t	input_length,
		size_t *	output_length
	)

Encode binary data as base64 (RFC 4648) characters in a new buffer.

(Credit: stackoverflow user ryyst)

Parameters

data	A pointer to the data to encode
input_length	The number of input bytes to encode
output_length	a pointer to location to receive the encoded length (4 * ceil(input_length/3), '=' padded; the buffer is NOT NUL terminated)

Returns

A pointer to a newly allocated buffer of size output_length, or NULL if calloc failed. Caller frees.

das_b64_decode_buf()

DAS_API int das_b64_decode_buf	(	const char *	data,
		size_t	input_length,
		unsigned char *	out,
		size_t	out_cap,
		size_t *	output_length
	)

Decode base64 (RFC 4648) into a caller-provided buffer, no allocation.

Parameters

data	The base64 characters (length a multiple of 4, '=' padded)
input_length	The number of base64 characters
out	The caller's output buffer
out_cap	The capacity of out
output_length	receives the number of decoded bytes written. Decoded output is at most 3/4 of input_length, so: out_cap >= 3*input_length/4 always suffices.

Returns

DAS_OKAY, or a negative das error code on malformed input or a short output buffer.

das_b64_decode()

DAS_API unsigned char * das_b64_decode	(	const char *	data,
		size_t	input_length,
		size_t *	output_length
	)

Decode base64 (RFC 4648) into a newly allocated buffer, symmetric with das_b64_encode.

Caller frees. Returns NULL on malformed input or alloc failure (with *output_length set to 0).

Note

For repeated decoding, use the no-alloc function das_b64_decode_buf().

dascmd_isArg()

bool dascmd_isArg	(	const char *	sArg,
		const char *	sShort,
		const char *	sLong,
		bool *	pLong
	)

See a given string matches the short or long form of an option.

This is commonly used in loops over each command line argument. It works for arguments in the form:

-a value –my-arg=value

The form that has spaces between the long option name and the value is not supported

Parameters

sArg	- A string to test
sShort	- The short form of an option
sLong	- The long form of an option
pLong	- If not NULL, the associated bool value is set to true if the long form of a argument was found.

Returns

true if the string matches the given option, false otherwise

dascmd_getArgVal()

bool dascmd_getArgVal	(	char *	sDest,
		size_t	uDest,
		char **	argv,
		int	argc,
		int *	pArgIdx,
		const char *	sShort,
		const char *	sLong
	)

Get the value of an argument if the current entry in argv matches either the short or long form of an option.

This is typically used to test command line arguments in a loop. It works for arguments in the form:

-a value –my-arg=value

The form that has spaces between the long option name and the value is not supported

Parameters

sDest	- The location to receive the option value
uDest	- The size of the location to receive the option value Note the macro DAS_FIELD_SZ is useful for getting the size of a field in a structure.
argv	- The list of command line parameters
argc	- The number of command line parameters
pArgIdx	- A pointer to the current argument index. It is incremented if the option is found.
sShort	- The short form of the option
sLong	- The long form of the option

Returns

false if the argument was not found or the option value missing often the argument, true otherwise and the index at pArgInd is incremented.

See also

also DAS_FIELD_SZ